dma: of: Fix of_node reference leak

of_dma_request_slave_channel() currently does not drop the reference to the
dma_spec of_node if no DMA controller matching the of_node could be found. This
patch fixes it by always calling of_node_put().

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Jon Hunter <jon-hunter@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/of-dma.c

@@ -221,12 +221,13 @@ struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
 
 		ofdma = of_dma_get_controller(&dma_spec);
 
-		if (!ofdma)
-			continue;
-
-		chan = ofdma->of_dma_xlate(&dma_spec, ofdma);
+		if (ofdma) {
+			chan = ofdma->of_dma_xlate(&dma_spec, ofdma);
 
-		of_dma_put_controller(ofdma);
+			of_dma_put_controller(ofdma);
+		} else {
+			chan = NULL;
+		}
 
 		of_node_put(dma_spec.np);